Freight containers, simply referred to as `containers`, are in extensive use for both civil and military storage and/or transportation of different types of items by sea, train, container trucks or aircrafts etc. The containers are constructed by a framework of steel having a floor, side walls and roof of flat or profiled plates. Usually the containers are provided with swing doors at one of the short ends.
In military applications, containers are used for transportation of equipment such as weapons, clothing, tools etc. from a warehouse to a combat area, where the containers are unloaded when needed and then abandoned. In an attempt to put such containers to further use, efforts have been made to form openings in the container walls to provide doors, windows and similar. However, this solution is not satisfactory for several reasons: firstly, it is not possible to establish a sufficient sealing against gas, and secondly, the containers will no longer be suited to their original purpose unless substantial repair is performed after the containers have served their secondary role.
U.S. Pat. No. 3,061,134 describes a container which has a construction for singular use and for use as a combination of two container units connected end to end. This is obtained by providing an end surface of the container unit with a ribbon-shaped sealing means 35 encircling the aperture of the front door 21 of the container unit. Moreover, the front door exhibits stop means 36 having an extension corresponding to the sealing means to decrease pressing load to the sealing means 35 and to protect the latter from mechanical load both in a mounted situation and in a free-standing situation.
In a connected state, a substantially correspondingly shaped second container unit is guided towards a first container unit to establish surface contact between their respective sealing means 35 and stop means 36. The container units are kept together in such a surface to surface contact by means of locking means 42 arranged at the corners of the aperture, in which the respective locking means 42 in general comprises a bar 43 extending through a bore at the edge of the front door, a locking pin 61 to lock the bolt within the bore including lever 56 to bring the bar 43 from a locked to an open state, and conversely.
Within this construction, the (relatively narrow) sealing 35 is established only at the contacting surface of the respective container units. This design in combination with the stop means 36 requires an exact positioning of the container units in a connecting procedure. Moreover, the combination of the sealing 35 and stop means 36 is not expected to offer a sufficient sealing effect to establish a sufficient overpressure or underpressure within the internal container space. Another substantial difference between this prior art construction from the present invention is that the locking or clamping means 42 exhibits a relatively long physical extension and will therefore extend partly into the aperture established after the connection. Accordingly, a design of this type will strongly limit the possibilities of establishing a free passage, for example, through the connected containers. Moreover, the prior art construction is not at all suited for connecting any form of a connection between more than two containers.